Plate for boilers



(No Model.) 2 Sheets-Sheet 1.

' A. H. EMERY.

PLATE FUR BOILERS.

N0. 322,051. Patented July 14, 1885.

INVENTOR WITNESSES n. 9mm momma. val-m n. c.

(No Model.) 2 Sheets-Sheet 2.

A..H.EME RY.

PLATE FOR BOILERS.

No. 322,051. v Patented July 14, 1885.

WITNESSES luvcm-oa u, versus. PhnmrLilhog-npher, mm n. c

PATENT rrrcn,

ALBERT H. EMERY, OF STAMFORD, CONNECTICUT.

PLATE FOR BOILERS.

SPECIFICATION forming part of Letters Patent No. 322,051, dated July;14, 1885.

Application filed April 13, 1883.

To (ZZZ whom, it may concern:

Be it known that I, ALBERT H. EMERY, of Stamford, in the county ofFairfield and State of Connecticut, formerly of the city, county, andState of New York, have invented certain new and useful Improvements inthe Mann facture of Boilers, Ships, and other riveted work from MetallicPates, of which the following is a specification.

The object of my invention is to increase the strength of metallicplates used in the manufacture of riveted, bolted, and like work-such asboilers, ships, &c.and also to increase the strength of structures madeup from such plates. To this end Isubj ect the marginalparts of the.plates through which the bolt or rivet holes are to be made tocompression between rolls or dies while in a cold or moderately heatedstate, so that the limit of elasticity in the reduced section of thispart of the plate, after punching or drilling will be at least as greatas the whole section of the unpunched portions, and, when practicable,of equal or greater ultimate strength; or, if preferred, my inventionmay be carried out by compressing the metal around the bolt or rivetholes or the places where they are to be made to a sufficient distanceto extend beyond the heads of the bolts or rivets. In the latter mode ofcarrying out my invention it is preferred to have the compressedportions extend to a sufficient radial distance to overlap one another.

Another mode of carrying my invention into effect, which possesses somespecial advantages, consists in compressing the metal around the bolt orrivet holes while the punch is in the hole or after the insertion of thebolt or rivet. In this case the meta], under pressure of the dies, isforced closely against the surface of the punch or against the bolt orrivet, as the case may be.

Under either mode of carrying my invention into effect the dies or rollsare formed in such a manner as to exert a reduced pressure on the metalat points adjacent to those at which the maximum condensing pressure isapplied,which reduced pressure, while insufficient to cause flowing ofthe metal, gives friction on the pressing surfaces sufficient to preventflowing under the greater pressure applied where the metal is to becondensed, and which condensing pressure would cause flow- (No model.)

ing of the metal if such flowing were not resisted by confining theadjacent metal by pressure and consequent friction,as stated, by asurrounding area of less pressure.

One or more plates, prepared by condensing the metal at or near themargins and punching or drilling, as explained, are connected byriveting or bolting as usual, after which, in the case of steam-boilersand other similar structures, the structure is subjected to internalhydraulic pressure sufficient to stretch the metal beyond its elasticlimit imparting a permanent set, and resulting in a higher elasticlimit, and increased rigidity and ultimate strength in the metal. Thestrength of the structure is thus materially increased, not only by theresults last stated, but because by the stretching operation all partsof the metal acquire such a set that in the future use of the structurethe various parts of the plates and all the rivets or other fasteningswill be equally strained, so far as practicable, instead of one beingrelieved at the expense of another, as is the case where the plates aresimply riveted together in the usual way.

It will be apparent that a boiler or other structure having beenstretched in the manner described, so as to impart a sufficient permanent set to the metal, will be prepared to endure its proper strainsin use without distortion or overloading any of its parts.

My invention is manifestly applicable to plates of various shapes,according to the various purposes for which the structures are designed.The said plates may be in fiat or bar form, or in the shape ofangle-irons, or irregular in shape. It often happens that some holes areso located, by reason of the peculiar form of the plate or structure, orfrom other causes, that the compression of the metal around such holesis impracticable or unnecessary. In all such cases the stretching of thestructure, so as to impart a considerable permanent set and bring allparts under equable strain, is highly beneficial.

Various modes of carrying my invention into effect are illustrated inthe accompanying drawings.

Figure 1 is a plan of a punched plate, indicating by dotted circles theareas of compressed metal around the rivet-holes. 1 represents theplate, and 2 the rivet-holes therein. 3 are the areas of condensed metalsurrounding the rivetholes, and I the annular spaces surrounding thecondensed portions 3 and overlapping each other, where the metal iscompressed and held with sufficient force to prevent the flow of metalfrom the inclosed portions 3 under the heavy pressure applied thereto topermanently condense the metal.

Fig.2 is a sectional view illustrating the condensing and punchingoperations. 5 represents a bed-die with an aperture, 6, to dis chargethe punchings. 7 represents the upper compressing-die, and 8 a punchworking therein, and driven by a hydraulic ram or other adequate andusual means, so as to perforate the plate 1. The compression-die 7 isalso pressed down by a hydraulic ram or other adequate means withsufficient force to condense the metal in that portion of the plate 1 onwhich it acts, so as to impart a permanent set. The face of the said dieis formed with a precisely straight or level face from 7 to 7, so as toexert its maximum pressure over this area and permanently condense themetal in the portion 3 of the plate, and with a very slightly recedingsurface from 7 to the margin 7, so as to apply over the annular surface4 a reduced pressure which, while insufficient to cause a flow of metalor produce any considerable condensation or permanent set therein, willsuflice to prevent any outward flow of metal from the incloscd portion 3to which the maximum pressure is applied to condense the metal. Thecompression and condensation of the metal may take place either beforeor after punching. In the latter case (which is the preferred mode) thepunch remains in the hole during the compression of the metal, and inthe former case the pressure is maintained during the punching.

Fig. 3 is a sectional view illustrating a mode of compressing andcondensing the metal during or subsequently to the riveting operation.In this figure 5 represents the bed-die; l l, the two parts of theplate; 8, a rivet connecting them, and 9 the riveting-tool. The face ofthe said tool is so formed from 8 to S as to apply condensing pressureand permanent set to the parts 3 of the plates, and between S" and themargin 8 to apply reduced pressure to the surrounding part, so as toprevent outward flow of metal from the central part, where the maximumpressure is received, as before explained.

I am aware that in the ordinary punching of metal plates somecondensation of the metal necessarily occurs around the hole, especiallynear the lower side or that next to the die; but this condensation isnot sufficient in degree or extent to accomplish the object of myinvention.

I am well aware that the condensation of metal by pressure, either whilehot or cold, is not broadly now.

My invention relates to the treatment of metal while in a cold ormoderately-heated state, so that permanent set may be given, and,furthermore, to the condensation of specitic parts of the plates, as andfor the purposes hereinbefore explained.

By the expression cold or moderatelyheated, I mean that the metal mustnot be so heated as to impart free ductility to it or adapt it to lloweasily under pressure, as in the customary operations of forging andswaging. A boiler plate cold-rolled throughout, so as to be condensedequally all over, will, when subjected to strain, tear first in thepunched portion, owing to its reduced section.

Having thus described my invention, the following is what I claim as newtherein and desire to secure by Letters Patent:

1. A plate or plates of metal for bolted or riveted work, having agreater density, strength or limit of elasticity in the metal in theparts through which bolts 01' rivets are passed or to be passed, thesaid increased density, strength, and limit of elasticity being producedby compressing the said parts of the plates while in a cold ormoderatelyheated state to a sufficient degree to impart a permanent set,as herein set forth.

2. A plate for the nmnufacture of boilers, ships, or bridges, or forother like purposes, compressed, while in a cold or moderatelyheatedstate, around the belt or rivet holes, or the places where such holesare to be made, to a sufficient distance to extend beyond the heads ofthe belts or rivets.

3. A plate for the manufacture of boilers, ships, or bridges, or forother like purposes, compressed, while in a cold or moderatelyheatedstate, around the bolt or rivet holes to a sufficient radial distance tocause said compressed portions to overlap each other, or nearly so.

4. A plate for the manufacture of boilers, ships, or bridges, or forother like purposes, compressed, while in a cold or moderatelyheatedstate, immediately around the parts where bolt or rivet holes are madeor to be made, and to a less degree around such compressed portion, soas to arrest or prevent the radial or outward flow of metal in the actof compressing the parts immediately around the holes.

5. A plate or plates for the manufacture of boilers, ships, or bridges,or for like purposes, having punched or drilled holes, and wit-l1 themetal compressed in a cold or moderately heated state around the belt orrivet holes to a sufficient extent to produce radial pressure against apunch, drill, belt, or rivet therein contained, substantially as setforth.

6. A boiler plate or plates connected by bolting or riveting andsubsequently stretched, so as to impart a permanent set and greaterrigidity and strength to the body.

ALBERT I-I. EMERY.

\Vitncsses:

OCTAVIUS KNIcirr, HARRY E. Kxrcn'r.

